Light bulbs based on light emitting diodes (LEDs) are commonly powered from an AC line, which is typically at voltages between 100 and 277 Volts Alternating Current (VAC) and at nominal frequencies of 50 Hz or 60 Hz. Strings of LEDs are typically used in such light bulbs. Each such string is made up of multiple serially connected LEDs. Although the LED light bulb is powered from the AC line, the LEDs themselves require direct current (DC). And, in order to avoid damage to the LEDs of the light bulb, the current supplied to the LEDs must not exceed the maximum DC current rating specified by the LED manufacturer. The voltage developed across an LED for a given current varies by a small but significant amount from one LED to another, and over time and temperature.